1. Field of the Invention
The present invention relates to an apparatus and method for detecting a tilted disc and for reproducing data recorded on the disc, and more particularly, to an apparatus and method for detecting a tilted disc using a focus error signal and for reproducing data recorded on the tilted disc.
2. Description of the Related Art
Optical discs are designed to be manufactured in a flat shape in which the plain of the recording surface is supposed to be parallel to the horizontal axis of the disc. However, a slight tilt, i.e., an inclination angle of a recording surface can be found in most optical discs. This tilt is result of disc distortion occurring during the injection and curing operations of the manufacturing process. An optical disc in which the recording surface is not perfectly parallel to the horizontal axis is referred to as a tilted disc.
FIG. 1 illustrates an example of a tilted disc. An optical disc of with a recording surface that is offset in an upward direction with respect to a level reference surface, is referred to as a positive tilted disc. An optical disc with a recording surface that is offset in a downward direction with reference to a level reference surface, is referred to as a negative tilted disc. Positive tilted discs and negative tilted discs are referred to as a radial tilted discs.
Data cannot be correctly read from a tilted disc when the tilt degree exceeds a tolerance limit. If the tilt degree exceeds a tolerance limit when data is read from a tilted disc, the data cannot be correctly read. When an apparatus for reproducing data from an optical disc cannot recognize the optical disc due to excessive tilt data reproduction is not possible.